Real Time Radiation Monitoring of Our Air & Water
From Industrial, Accidental, and Terrorist Events
A. Threats and Scenarios:
The first Step in preparing ourselves is to try to predict or imagine events we are
preparing for.
 Terrorism:

o Small Nuclear Bomb – One of the Russian suit case bombs.
o Conventional Car Bomb perhaps with powdered Cesium or Medical
Waste, etc. (Dirty Bomb)
o Water Contamination: A terrorist sneaks into reservoir and dumps in
radioactive liquids, which they have stolen from a hospital, nuclear
pharmacy, or elsewhere.
Industrial Accident: Many facilities in the USA handle or store radioactive
materials. Including Universities, Hospitals, National Laboratories, Pharmaceutical
and Biotech Companies, Nuclear Power Plants, also gauge makers and
nondestructive testing companies, oil and mining exploration companies.
o Airborne or Waterborne
o Luckily there is not a threat of another Chernobyl in the USA – The
Flammable Carbon Core is only used in Russian Reactors.
o A fire, explosion, or spill at an industrial facility
o Pollution, liquid run off, smoke stack emissions
B. Detection:
First thing to do after an incident is to get the facts. This requires the correct
detectors. (Strategic use and advance placement of detectors will help prevent
misuse and unlawful transport of Radioactive Materials.)
I. Physical Form of Material
o Air or Water born particulates, catch it on a glass fiber filter disk, so it can be
measured.
o Reactive Chemicals or vapors: Example Iodine (catch it in a Charcoal cartridge)
o Noble gases and compounds: Unlikely, not a problem if ventilation is good.
o Water Born Ionic and Nonionic salts
II. What Radiation does it emit?
o
o
o
o
Alpha
Beta
Gamma
Neutrons or Positrons
TA
TECHNICAL ASSOCIATES
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www.tech-associates.com
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III. Choosing Your Detector Type
TYPE
GM TUBE
Pro

High Count Rate = Good Sensitivity
(Gas Filled)

Can see Alpha, Beta, some Gamma 



Low Cost
Not sensitive to Voltage Change
Not sensitive to Temperature

Low Gamma Sensitivity
Compared to Scintillators
Old Models May read low or
Zero in very high fields
Energy Dependent
Gamma Scintillation


High Sensitivity
Good Energy Resolution

Highest Cost
Specialized
Scintillation

Distinguish Radiation Type

Need Multiple Detectors



Alpha Scintillators
Beta Scintillators
Slow & Fast Neutrons
Plastic Scintillation


Large Volume
Low Cost


Very Little Energy Info
Not useful for Isotope
Identification
Ion Chamber

Gives mR/h, not counts per min.


Widest Range – can go 6 to 8
decades.
Not Affected by Voltage Changes
Least Sensitive to Environmental
Changes: temp., shock, pressure.

Needs High Radiation Level
(or large chamber) to work
More Costly


Con

Following Detectors are Used for Gamma Spectral Analysis and Isotope Identification:
 Wonderful Energy Resolution
 Needs liquid Nitrogen or
Cold Solid State
Really good little freezer
Detectors
 Small Detectors give Low
Count Rate
Room Temp.
Solid State Detectors

Pretty Good Energy Resolution

Room Temperature Operation
TA

Small Detectors give Low
Count Rate
TECHNICAL ASSOCIATES
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7051 ETON AVENUE, CANOGA PARK, CA 91303  TELEPHONE (818) 883-7043  FAX (818) 883-6103
www.tech-associates.com
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TYPE
Gas Filled, Sealed,
Proportional Detectors
Gamma Scintillation –
NaI(Tl)
Pro
Con

Give Energy Information

Low Gamma Sensitivity

Good for Betas, Fair for Gammas

Gas Can Leak



Available in Large Crystals for very
High Sensitivity/Count Rate.
Decrease in Background

Room Temperature Operation


Allows for Isotope Identification


Increase Sensitivity

Typical 7.5% Energy
Resolution
Requires Gamma Spec
Detector
Some are Temperature and
Voltage dependant
But Helpful if the Isotope
being looked for is known
Still Fragile

 Energy Analysis
o Single Channel – looks at one peak or a small group of peaks
o Multi-Channel – shows entire spectra
o Area Region of Interest
 Other Considerations
o
o
o
o
o
Geometry
Window Material
Filters and Pumps
Electronics
Software
C. Deployment and Logistics:
This gets back to the impossible task of predicting the details of a surprise attack.
 Portable Equipment
o The Highway Patrol, Fire Fighters and Ambulances respond to road
accidents. A vehicle carrying radioactive material, or a pipe/car bomb with
radioactive material included in its construction, need to be detected
immediately so the least amount of damage will be done. If properly and
immediately dealt with, these types of incidents will not escalate into
contamination of the environment or the populace.
o What is needed:
 Specialized Pocket Dosimeters (scintillation ZnS or BGO the best
for this) to alert the carrier to the presence of radioactivity.
 Portable survey meter to identify what is radioactive.
 Water sampling monitors to check for contamination.
 Air monitors, to see if an area needs to be quarantined.
TA
TECHNICAL ASSOCIATES
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7051 ETON AVENUE, CANOGA PARK, CA 91303  TELEPHONE (818) 883-7043  FAX (818) 883-6103
www.tech-associates.com
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 Stealth Attacks
o What if there was not an explosion or accident to alert us to the presence
of radioactivity. If an overt act of throwing a radioactive substance into the
drinking water reservoir, hoping to contaminate thousands of people.
o To protect against this constant real time monitoring of drinking water
must be in place, with alarms and auto dialers to notify the site manager,
even when offsite.
o Constant monitoring of the air of Federal Buildings, Congress, the White
House, and other vital targets may be necessary to prevent contamination.
 Who Can Be Called to Help?
o Our Health Physics Society has a network of experts available as first
responders or for advise. (Contacts available at our web site.)
o For Equipment Advice and system design, call Technical Associates for
recommendations.
o If radiation is detected, local Hazmat teams, or Radiation Safety Officers
at Universities must be contacted to help deal with the clean up.
If procedures and proper detection is in place, then in the event of an
accident or overt terrorist event, the radioactive material can quickly be
detected and dealt with before any long-term contamination or harm
happens.
TA
TECHNICAL ASSOCIATES
_
7051 ETON AVENUE, CANOGA PARK, CA 91303  TELEPHONE (818) 883-7043  FAX (818) 883-6103
www.tech-associates.com
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